Inner Classes Allowed in EJBs?

Can I not put an inner class inside my enterprise java beans? If not, why not?
javax.transaction.TransactionRolledbackException: try to access class com.blueorchid.ejbs.WorkflowtBean$Dummy from class com.blueorchid.ejbs.WorkflowtBean; nested exception is:
java.lang.IllegalAccessError: try to access class blueorchid.ejbs.WorkflowtBean$Dummy from class blueorchid.ejbs.WorkflowtBean
java.lang.IllegalAccessError: try to access class blueorchid.ejbs.WorkflowtBean$Dummy from class blueorchid.ejbs.WorkflowtBean

Nevermind. My mistake was in not declaring my inner class, Dummy, as public. After I declared it as public I no longer received the IllegalAccessError. It appears that one can use inner classes in EJBs. This topic is closed.

Similar Messages

Are enums and inner classes allowed in taglib function signatures??

Hi,
I have a taglib with the following function definition:
<function>
        <description>Determine if viewing a patient attribute is allowed</description>
        <name>isViewingPatientAttributeAllowed</name>
        <function-class>com.example.admin.authorization.UserAuthorizer</function-class>
        <function-signature>boolean isViewingPatientAttributeAllowed(com.example.bean.User, com.example.bean.Patient.PatientAttribute, com.example.bean.Patient)</function-signature>
        <example>
            ${ncvi:isViewingPatientAttributeAllowed(user, patientAttribute, patient)}
        </example>
</function>Where com.example.bean.Patient.PatientAttribute is an enum (note package names have been changed to protect the innocent;-). When I try to compile my web app I get the following error:
org.apache.jasper.JasperException: The class com.example.bean.Patient.PatientAttribute specified in the method signature in TLD for the function ncvi:isViewingPatientAttributeAllowed cannot be found. com.example.bean.Patient.PatientAttributeIf I change PatientAttribute to a static inner class of Patient, I still get the error. Are enums and inner classes allowed in function signatures?
Thx.

I think that you'll find it easier to define a non-inner abstract class RefBase, that exposes a removeFromQueue() method, then extend that for your Ref class. That way, the queue just deals with RefBase instances (or ? extends RefBase).
I think that any other approach is going to get the compiler confused, because the compile-time Ref depends on the parameterization of its defining class.

Static inner class causes deployment on OC4J 10.1.2 to fail

Hi,
this issue has already been raised on OC4J 9.0.4 with J2SDK 1.4.2 (see EJB fails to compile - static inner class problem
Recap: When referencing static inner classes in an EJB, the deployment fails. During the generation of the wrapper classes, a signature <package>.<outer class>.<inner class> gets converted to <package>.<outer class>$<inner class>, which is syntactically wrong. While the Java 1.4.1 compiler kindly ignores this syntax error, its 1.4.2 counterpart complains - and fails.
@Oracle: When will this bug be fixed for OC4J 10.1.2?
Best regards,
Holger

Holger,
Don't static inner classes contradict the EJB specification?
In any case, in answer to Andy's question: If you wish to file this as a bug, you can do so via the MetaLink Web site.
[In fact, [i]MetaLink is your only option for submitting bugs for Oracle products -- as far as I know.]
Good Luck,
Avi.

OJC error w/ assert & inner class

The following code generates an error:
public class Foo {
public class Bar {}
public Foo() {}
public static void main(String[] args) {
assert false == true:"Foo Bar";
ojc Foo.java -source 1.4 -classpath c:\j2sdk1.4.1\jre\lib\rt.jar -verbose
[jdk location retrieved from JAVA_HOME environment variable: c:\j2sdk1.4.1]
[classpath: c:\j2sdk1.4.1\lib\rt.jar;c:\j2sdk1.4.1\lib\i18n.jar;c:\j2sdk1.4.1\li
b\sunrsasign.jar;c:\j2sdk1.4.1\lib\jsse.jar;c:\j2sdk1.4.1\lib\jce.jar;c:\j2sdk1.
4.1\lib\charsets.jar;c:\j2sdk1.4.1\classes;c:\j2sdk1.4.1\jre\lib\rt.jar]
[sourcepath: c:\j2sdk1.4.1\jre\lib\rt.jar]
[encoding: default]
makeLevel = 1
[parsing C:\temp\Foo.java [loading c:\j2sdk1.4.1\jre\lib\rt.jar\java\lang\AssertionError.class 50ms]
[loading c:\j2sdk1.4.1\jre\lib\rt.jar\java\lang\Error.class 0ms]
[loading c:\j2sdk1.4.1\jre\lib\rt.jar\java\lang\Throwable.class 0ms]
[loading c:\j2sdk1.4.1\jre\lib\rt.jar\java\lang\Object.class 0ms]
[loading c:\j2sdk1.4.1\jre\lib\rt.jar\java\io\Serializable.class 0ms]
60ms]
[loading c:\j2sdk1.4.1\jre\lib\rt.jar\java\lang\Class.class 0ms]
[loading c:\j2sdk1.4.1\jre\lib\rt.jar\java\lang\String.class 0ms]
[loading c:\j2sdk1.4.1\jre\lib\rt.jar\java\lang\Comparable.class 0ms]
[loading c:\j2sdk1.4.1\jre\lib\rt.jar\java\lang\CharSequence.class 0ms]
[loading c:\j2sdk1.4.1\jre\lib\rt.jar\java\lang\RuntimeException.class 0ms]
[loading c:\j2sdk1.4.1\jre\lib\rt.jar\java\lang\Exception.class 0ms]
[flattening class Foo]
[flattening class Foo$Bar]
C:\temp\Foo.java:8: error #300: constructor AssertionError(<anything>) not found
in class java.lang.AssertionError
assert false == true:"Foo Bar";
^
Total build elapsed time = 70ms
[10 lines compiled in 70ms from 1 files, generating 0 classes]
1 error
The same code compiles fine with Sun's JDK 1.4.1 compiler. Removing the inner class allows the code to compile fine with OJC.
Is this a known OJC bug?
TIA,
David

It is a known bug that has been fixed in 9.0.4. We don't plan to ship 9.0.4
anytime soon. If you are using 9.0.3, send me an email to
[email protected] and I will send you a workaround. In your email
specify the JDev build number that you are using (please, see
about box).
Regards,
Michel

EJB fails to compile - static inner class problem

I am using OC4J 9.0.4 and Sun JDK1.4.2 and EJBs fail to compile if they reference objects that contain static inner classes. However, they successfully compile under JDK1.4.1.
For example, I have a class like below:
public class ValueObject
public static class Key
private Key key;
private String value;
Any references to ValueObject.Key inside the EJB cause the EJB compiler to generate "ValueObject$Key" which is incorrect. JDK1.4.1 is more lenient than 1.4.2, and allows this error through.
Is there a way around this problem other than reverting to JDK1.4.1?
Regards,
Andy

The reason I don't want to move to JDK 1.4.1 is because of the memory leak in the StringBuffer.toString() method.
Is there anywhere I can submit this as a bug?
Regards,
Andy

Reason for not allowing static declarations inside an inner class

Is the reason for not allowing static declarations inside an inner class is due to the fact that it can never be accessed at a class level as the outer class has to create an instance of the inner class and any attributes/methods of the inner class has to be accessed through that.
Typically, an instance (non-static) variable can never be accessed in a statement or expression inside a static context but the class variable can be accessed inside a non-static context. Given this, shouldnt the static declarations be allowed inside an inner class?
Correct me if my understanding is wrong.
Thanks

I still couldnt get it clearly. Why i cant i have a static value ( variable ) for all the instances of the inner class irrespective of its enclosing instances of it ( i.e outer class instances). Say in this example below,
class Outer
static int i = 0;
public Inner inner = new Inner();
class Inner // inner class ( non-static nested class )
int j = 0;
static final int k = 2; // compile time constants are allowed
// ininner class
public void m1()
j++;
System.out.println("j is " + j);
i++
System.out.println("i is " + i);
public static void main(String[] arg)
Outer outer1 = new Outer();
outer1.inner.m1(); // j will be 1 & i will be 1
Outer outer2 = new Outer();
outer2.inner.m1() // j will be 1 again & i will be 2. But I would
// want j to be 2. Why is this not allowed?
Looks like something missing..

Problem with Outer and Inner Classes....or better way?

Right now I'm trying to create an Inner class.
My .java file compiles ok, and I create my jar file too.
But when I try to instantiate the Inner class, it fails:
java.lang.NoClassDefFoundError: com/myco/vlXML/vlXML$vlDocument.
Here's the class code:
public class vlXML{
    private ArrayList myDocList=new ArrayList(); //holds documents
    public vlXML(){
    private class vlDocument{
        public vlDocument(){
        //stuff goes here
    public vlDocument vlDOC(){
        return new vlDocument();
    public void addDocument(){
        vlXML xxx=new vlXML();
        vlDocument myDoc=xxx.vlDOC();
        myDocList.add(myDoc);
    public int getNumDocs(){
        return myDocList.size();
}Then, from a jsp page, I call:
vlXML junk1=new vlXML();
junk1.addDocument();...and get the error...
Can someone help me figure out why it's failing?
Thanks....

You nailed it - thanks....(duh!)
While I have your attention, if you don't mind, I have another question.
I'm creating a Class (outer) that allows my users to write a specific XML file (according to my own schema).
Within the XML file, they can have multiple instances of certain tags, like "Document". "Document"s can have multiple fields.
Since I don't know how many "Documents" they may want, I was planning on using an Inner Class of "Document", and then simply letting them "add" as many as necessary (thus the original code posted here).
Does that seem like an efficient (logical/reasonable) methodology,
or is there there something better?
Thanks Again...

Interface and Inner Class

Hi,
In interface we can't provide method body.
but we can provide method body like this,
public interface TestInterface {
     public class Add {
          public int add() {
               return 100;
what is the logic behind Inner Class inside interface.
plz help.Thanks in advance.

there isn't really any logic to it, it's just something that's semantically possible. there wasn't a conscious decision to allow this, it's just a by-product of the enclosing types mechanism, and while it wouldn't be a good idea to do this, there's no technical reason why it shouldn't be possible, either

Inner class vs. imported class

Hi everyone,
I have entitiy beans created for a client's web app I'd like to use in the
web service using WebLogic Workshop 7.0. Say the classes are imported like
this in the services:
import com.hoike.clientname.ap.bean.Invoice
import com.hoike.clientname.ap.bean.Vendor
Instances of these classes are used in callback methods and some of the
service methods.
When I generate the CTRL file, it actually adds those imported classes as
inner class of the service defined.
The problem is that when I try to used these services from another service,
I cannot use the imported classes (as Invoice or Vendor), but instead I have
to use the inner class (InvoiceService.Invoice or VendorService.Vendor)
Does WebLogic Workshop 7.0 only allow you to use inner classes? Is there a
way to use custom classes as method parameters?
Thanks in advance!
Makoto

how do you declare your inner class?
Is it (public)
public static class MyInnerClassor (private)
private static class MyInnerClassor (package)
static class MyInnerClassor (protected)
protected static class MyInnerClassTry to change the way you declare the inner class. Use protected or package or public instead.

SerialVersionUID and inner classes

Hello All
A quick question about serialVersionUID in inner classes.
If an inner class can't have any static members, how come it's legal to define
static final long serialVersionUID = 123L;
in an inner class ? Is there something special about serialization that allows this ?

there is nothing special about the serialVersionUID defintion -
you can define static datamember of inner class as long as it is final or the inner class is static :
public class Out {
public Out() {
private class In {
static final int i1 = 1; //legal
static int i2 = 2; //** illegal
private static class InStatic{
static final int i1 = 1; //legal
static int i2 = 2; //legal
}

Accessing Enclosing Class Members From Inner Class Subclass

I have the following scenario that I cannot get to work. Notice the comments in B.doWork() for the problem code. In B.doWork(), how do I access m_strA?
* A.java
* Created on July 5, 2002, 2:20 PM
package Projects.InnerTrouble.Files;
public class A {
     public abstract class InnerA {
          public abstract void doWork ();
     public String m_strA;
     /** Creates new A */
     public A ()
               new InnerA() {
                         public void doWork ()
                                   System.out.println("A$InnerA$1's doWork() called!");
                                   m_strA = "Annonymous subclass of InnerA's doWork did this";
                    }.doWork();
     * @param args the command line arguments
     public static void main (String args[])
               A oTemp = new A();
               System.out.println(oTemp.m_strA);
               B.getB(oTemp).doWork();
               System.out.println(oTemp.m_strA);
class B extends A.InnerA {
     public B (A a)
               a.super();
     public void doWork ()
               System.out.println("B's doWork() called!");
               // How do I access m_strA within B's doWork() method? The following is what I would expect to be the answer, but it does not compile
               // A.this.m_strA = "B's doWork did this";
     private static A.InnerA sm_oInnerA;
     public static A.InnerA getB (A a)
               if (sm_oInnerA == null)
                    sm_oInnerA = new B(a);
               return (sm_oInnerA);

The whole point is that B is not an inner class of A
so it does not have access to A's member variables.
Eventhough B extends an inner class of A, that does
not make B an inner class of A. That is in the JLS,
but not so elegantly as I have put it, hehe.
If B were an innerclass of InnerA, then it would
qualify to access A's member variables.OK, I think that you are finally getting through to my thick skull on this one. Let me restate and get your check-off on my understanding of the situation.
The only classes with access to A's this reference are A and inner classes of A that are found within the definition of A. So, despite the fact that A and B are in the same package (and B should have access to A's non-private members because B and A are in the same package), and despite the fact that we would normally state that B "is a" InnerA (which is an inner class of A and would have access to a reference to the A.this reference), B is not allowed access to A.this (because B "is not really a" InnerA in the same way that the anonymous implementation of InnerA "is a" InnerA). However, nothing would prevent me from giving B access to a reference of the enclosing A as long as it was done via a method of InnerA, and as long as the implementation of that method is contained in A's implementation.
Does this "access" rule realy make sense? Are you aware of the justification for this rule? Or is the justification stated in the JLS? I would think that the compiler ought to be able to figure this kind of thing out and allow it. It seems to me the fact that I defined B in the way that I did, and the fact that B "is a" InnerA, implies that I desired a fairly tight relationship to A. In fact, I desired the exact relationship that exists for the anonymous implementation of InnerA.
The following is a modified version of my original example that runs as I originally wanted it to, but works around the access rules discussed on this forum thread:
* A.java
* Created on July 5, 2002, 2:20 PM
package Projects.InnerTrouble.Files;
public class A {
     public abstract class InnerA {
          public abstract void doWork ();
          /** added to allow implementors of InnerA that are not enclosed in A's class definition to have access to the enclosing class */
          public A myEnclosingInstance ()
                    return (A.this);
     public String m_strA;
     /** Creates new A */
     public A ()
               new InnerA() {
                         public void doWork ()
                                   System.out.println("A$InnerA$1's doWork() called!");
                                   m_strA = "Annonymous subclass of InnerA's doWork did this";
                    }.doWork();
     * @param args the command line arguments
     public static void main (String args[])
               A oTemp = new A();
               System.out.println(oTemp.m_strA);
               B.getB(oTemp).doWork();
               System.out.println(oTemp.m_strA);
class B extends A.InnerA {
     public B (A a)
               a.super();
     public void doWork ()
               System.out.println("B's doWork() called!");
               // The following is what I would expect to be the answer, but it does not compile
               // A.this.m_strA = "B's doWork did this";
               // added myEnclosingInstance() to get functionality desired above
               myEnclosingInstance().m_strA = "B's doWork did this";
     private static A.InnerA sm_oInnerA;
     public static A.InnerA getB (A a)
               if (sm_oInnerA == null)
                    sm_oInnerA = new B(a);
               return (sm_oInnerA);
}

Why and how to use "inner class"

When i am learning advanced java language features,
i could not understand why and when to use the "inner class",
who can give me some examples?
Thanks!

You would use an inner class when an object needs visibility of the outer class. This is akin to a C++ friend.
An example of this is an iterator. An iterator over some collection is typically implemented as an inner class of the collection class. The API user asks for an Iterator (from the Collection) and gets one - in fact they receive an instance of an inner class, but doesn't care. The iterator needs to be inner, as the iterator needs to see the internal data structures of the outer (collection) class.
This could also be done with an anonymous class, as mentioned by spenhoet above. However, in the case of a collection, the role of the iterator is clear - thus it deserves its own class. And often there is more than one place an iterator can be returned (e.g. see java.util.List, which has several methods that return Iterators/ListIterators), thus it must be put in its own class to allow reuse of the code by outer class.

Why can't inner classes have static methods?

I just tried to add a static method to an inner class, which would have been useful for extracting constants about said inner class, and it turns out that is not allowed.
Of course I have other ways to code what I wanted, but I'm curious as to why this restriction was set in place. Anybody know?

Probably because an inner class is tied to an instance of the enclosing class. I think that, conceptually at least, the inner class' definition itself only exists in the context of an instance of the enclosing class. While I'm sure it would have been technically possible to allow it, it would be confusing and not make a whole lot of sense--what is the static context for the inner class, since the class only exists in a non-static context?

I don't understand the design of inner class private member

This is a question about the java language specification of inner classes.
In the java langage specification document, we read
If the member or constructor is declared private,
then access is permitted if and only if it occurs
within the body of the top level class (�7.6)
that encloses the declaration of the member.
This allows following code :
public class PrivateTest {
    public PrivateTest()
      Hello hello = new Hello();
      System.out.println(hello.secret);
    class Hello
       private String secret = "This is a secret";
} wherein accessing the private secret field is allowed
from into the PrivateTest enclosing class.
My questions are :
a) It seems that private methods or constructors of
inner classes have no meaning, we could also declare
them as public. True or false ?
b) Is there any reason that Java bypass this private
mechanism ?
c) Why is the above definition not written with
"first enclosing" instead of "top level" ?
Thanks in advance

Private methods and constructors of an inner class can only be accessed within the outer class. Other classes can't instantiate it or use the private methods.
You can also make your inner class private, so it is not possible to refer to the class from outside (and thereby another way of preventing it from being instantiated).
So it does matter which access modifiers you use.
I think top level is more precise than first enclosing, because you can have inner classes in inner classes, which are still available for the top level class (haven't tested this).

Method local Inner class

Why method local class can access only the final varaible of the method?
I found somewhere that this is because the non-final local variables go out of scope after method completion, but i wonder final local variables also reside on the stack.
class MyOuter2 {
private String x = "Outer2";
void doStuff() {
String z = "local variable";
class MyInner {
public void seeOuter() {
System.out.println("Outer x is " + x);
System.out.println("Local variable z is " + z); // Won't Compile!
} // close inner class method
} // close inner class definition
} // close outer class method doStuff()
}

pxNet wrote:
and so you are now saying it accesses the original variable, not a copy of it?No, I'm not saying that at all; see reply #1. The situation is quite the opposite, the inner class accesses a copy of the variable. Direct access to the local variable is most definitely not allowed. But that doesn't have anything to do with parameter-passing semantics.
I'll try to clarify with another demonstration of the problem. Assume that direct access to non-final local variables was actually allowed, and that the following example would compile (it won't, of course): class Outer {
    Inner method() {
        Object o = "foo";
        return new Inner() {
            public void modifyLocalVariable() {
                o = "bar";
    interface Inner {
        void modifyLocalVariable();
    public static void main(String[] args) {
        Inner inner = new Outer().method();
        inner.modifyLocalVariable(); // what local variable is this modifying?
                                     // the local variable in method() has gone
                                     // out of scope!
}Because of the way anonymous inner and local classes are implemented, they get a copy of the local variables (per the JLS). Mind you, there isn't any parameter passing going on at all in this example.
~

Inner Classes Allowed in EJBs?

Similar Messages

Maybe you are looking for